Old People Do Smell, But It's Not That Bad

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The distinctive "old person smell" you may have picked up on when
visiting your grandparents most likely wasn't your imagination, a
new study indicates.

When given whiffs from pieces of pads worn under the armpits of
young, middle-aged and elderly people for five consecutive
nights, study participants could reliably distinguish the
body odor of the elderly, who were 75 and older, the
researchers found.

"The results of this study support the cross-culturally popular
concept of an 'old person odor,'" writes the international team
in a study published today (May 30) in the journal PLoS ONE.

The notion that the elderly have a distinct smell exists in
multiple cultures, and usually the odor is said to be
unpleasant. But this probably has more to do with negative
perceptions of old age, rather than with the odor itself,
according to study researcher Johan Lundström, an assistant
professor at the Monell Chemical Senses Center in Philadelphia.

In the study, participants rated the smell of the elderly people
as less intense and less unpleasant than the body odor of young
people (20 to 30 years old) and middle-aged people (45 to 55
years old). This effect was driven by how the participants rated
the body odor from men, who appeared to smell the worst and the
strongest in middle age. The odor
from women of all ages was rated as less intense than men,
and closer to neutral smelling for the young and middle-aged.

The team used young people to do the sniffing for two reasons:
They were more plentiful as volunteers and using participants
from different age groups could potentially introduce a new layer
of complexity, if age of the smeller influences how body odor is
perceived, Lundström said.

He cautioned that while the participants did appear able to
distinguish the elderly body odor, discriminating between age
categories and correctly labeling odors from the elderly, they
did not demonstrate a strong talent for it and showed low
confidence in their abilities. [ Personality
Traits Affect How We Smell ]

It's not yet clear why body odor changes as humans age or why
humans are able to pick up on these changes.

Body odors originate from an interaction between skin gland
secretions and bacteria on our skin. As people age, the activity
of different types of skin glands changes. This factor may
contribute to the perceived change in body odor with age, the
researchers write.

So far, scientists can only speculate on why this apparent signal
for old age exists. Research in other animals indicates that such
an odor may act as a sign of the "good genes" that have allowed a
male to live into old age, making him more
attractive to females. It's also possible the distinctive
odor is not a direct result of age; for instance, it could be
associated with increased inflammation (part of an immune
response) within the bodies of the elderly, Lundström said.